Fix typos

ci/images/centos7/Dockerfile

 FROM centos:7
 
 RUN curl -sL https://rpm.nodesource.com/setup_14.x | bash - && \
-      yum install -y nodejs &&
+      yum install -y nodejs && \
       npm install -g yarn
 
 RUN yum groupinstall -y 'Development Tools'
@@ -12,7 +12,7 @@ RUN npm config set python python2
 RUN yum install -y epel-release && yum install -y jq
 RUN yum install -y rsync
 
-# Copied from ../Dockerfile
+# Copied from ../debian8/Dockerfile
 # Install Go dependencies
 RUN ARCH="$(uname -m | sed 's/x86_64/amd64/; s/aarch64/arm64/')" && \
     curl -fsSL "https://dl.google.com/go/go1.14.3.linux-$ARCH.tar.gz" | tar -C /usr/local -xz